Atmosphere aerosol over Ukraine and Kyiv city under Russian invasion

We investigate the impact of the Russian invasion and military activities on aerosol parameters in the atmosphere over Kyiv and Ukraine using data from the AERONET Kyiv station, the AirVisual network, and the MERRA-2 reanalysis. We examined the annual impact of the war on aerosol characteristics (Angstrom exponent, aerosol optical depth, fine particle fraction, aerosol absorption optical depth, complex refractive index) and PM_2.5 specifically within the Kyiv city, using in situ observations from the AERONET and AirVisual networks. After the invasion, there was a short surge in PM_2.5 contamination. We also investigated the levels of SO₂, SO₄, PM_2.5 and black carbon before and at the onset of the full-scale invasion across Ukraine. The temporary improvement in air quality in Kyiv city is associated with a decrease in traffic load. AERONET observations reveal changes in the annual dynamics of the Ångström Exponent, with lower values observed in 2022 and a decrease in the fine aerosol fraction. Analysis of the aerosol complex refractive index indicates a shift in the dominant aerosol type present in the atmosphere. The AirVisual network data indicate no abnormal increases in PM_2.5 concentrations during 2022 and early 2023, although elevated values were observed due to military activities and fires. The comparison of the state and properties of aerosol contamination before and after Russia's invasion shows a significant increase in the black carbon concentration in both the eastern and western parts of Ukraine.